Added --deepColor option to SampleApp, triggers creation of a ten-bit/channel buffer on Windows.

include/views/SkOSWindow_Mac.h

Index: include/views/SkOSWindow_Mac.h
diff --git a/include/views/SkOSWindow_Mac.h b/include/views/SkOSWindow_Mac.h
index efa97bf87245c35ba9c873a8f3987836c2f7aa30..4558a58833a53a5b55dc895a1e3a1124b412a7f5 100644
--- a/include/views/SkOSWindow_Mac.h
+++ b/include/views/SkOSWindow_Mac.h
@@ -33,7 +33,8 @@ public:
     };
 
     void    release();
-    bool    attach(SkBackEndTypes attachType, int msaaSampleCount, AttachmentInfo*);
+    bool    attach(SkBackEndTypes attachType, int msaaSampleCount, bool deepColor,
+                   AttachmentInfo*);
     void    present();
 
     bool    makeFullscreen();